Ice fishing devices to signal that a fish has taken the bait are widely used and those that are constructed to position their reels under water when the devices are erected and set in place for use, are deservedly popular since their lines do not freeze as is often the case when the reels are above water then to prevent the flags from becoming operative to indicate that a fish has taken the bait.
Signal devices constructed to have their reels under water when in use have their flags held inoperatively positioned by a latch until tripped by the turning of the reel when the line is pulled by a fish taking the bait and starting to swim off with it. A common occurence is to have the flag accidentally released, usually by the wind, with the result the flag is erected even though the bait is untouched.